Spark plug



L. K. JAMES Sept. 19, 1933.

SPARK. PLUG Filed Aug. 24, 1931 Patented Sept. 19, 1933 UNITED STATESPA'naN'r OFFICE."

3 Claims.

This invention relates to a spark plug. I An object of the invention isto provide a spark plug of the character described having novel meansfor connecting the electrical conductor thereto.

Another object of the invention is to provide in a spark plug, a noveltype of connection serving the double purpose of connecting theelectrical conductor to the electrode of the plug and of inclosing andprotecting theouter end of the plug against moisture and other foreignmatter.

With the above and other objects in view this invention has particularrelation to certain novel features of construction, arrangement of partsand'use, an example of which is given in this specification andillustrated in the accompanying drawing wherein:

Figure 1 shows a side elevation of the plug partly in section,,and

Figure 2 shows a cross sectional view taken on the line 2-2 of Figure 1.

Referring now more particularly to the drawing wherein like numerals ofreference designate similar parts in each of the figures, the numeral 1designates the tubular jacket of the plug, composed of suitable metaland preferably made in two sections. The inner end of this jacket isreduced and threaded as at 2 for connection in to the motor cylinder inthe usual way. Within the jackets 1 there is the procelain 3 whose innerend is tapered or contracted as. at 4 and thus spaced from the inner endof the pocket.

This porcelain has the external annular shoulders ,5, 6 which areclamped between the opposing parts of the sections of the jacket 1 asshown in Figure 1. Extending axially through'the porcelain there is anelectrode 7, whose inner end is spaced from the terminal 8 which isgrounded on the jacket 1.

The outer end of the porcelain 3 has a deep socket 9 into which theouter end of the electrode extends, said extended end being threaded andscrewed onto said threaded end there is a nut 11 which carries theoutwardly extended flexible prongs 12, 12.

There is a cap 13 formed of suitable material such as bakelite, whichhas the inward tubular extension 14 which fits closely withinthe socket9. This extension 14 has a deep axial bore 15 in which there is locateda metallic plug 16, preferably brass, and a sleeve 17 is preferablyformed integrally with said plug and lines the inner end of saidbore 15.The prongs 12 fit closely within the sleeve 1'! when the, parts areassembled.

The cap 18 has a lateral extension 18 sleeve (Cl. 123-169) I t like inform and having the bore 19 to receive the conductor 20. The bore 19 isreduced and extended on through the plug 16 to receive the wire 21, ofsaid conductor and a screw 22 is threaded outwardly through the plug 16and its outer end 0 clamps the wire 21 securely in place. This screw hasan enlarged head 23 which fits closely within the sleeve 1'7.

The outer end of the jacket 1 is reduced as at 24 and the cap 13 fitsover said reduced portion 5 .forniing a flush joint with the jacket 1.

The outer end cap 13 may be readily pulled oif of the jacket when it isdesired to disconnect the plug from the. distributor and may be asreadily, replaced on the jacket, the prongs 12 fit- 7o ting closelywithin the sleeve 17-and forming an electrical connection between saidsleeve and the electrode 7 and the screw 22 forming an electricalconnection between said sleeve and the conducting wire 21. The cap 13will serve not only to form a strong connection for the terminal wire 21but will also protect the same against moisture and will also incloseand protect the outer end of the spark plug proper and will keep thesame dry. 4

The drawing and description disclose what is now considered to be apreferred form of the invention by way of illustration only, while thebroad principle of the invention will be defined by the appended claims.

.What 1 claim is:

1. In a spark plug having a jacket, an insu lator secured thereinprovided with an outer end socket, an axial electrode through theinsulator, contact prongs on said electrode in said socket; a detachablecap fitted over the outer end of said jacket and having an extensionwhich fits into said socket, a tubular contact sleeve in said extensioninto which said prongs fit, said cap having a lateral extension providedwith a bore for the reception of. an electrical conductor, a plugin saidcap at the outer end of said sleeve through which said bore extends, ascrew in said sleeve threaded through said plug and whose outer end v isadapted to engage and secure said conductor 100 in place. 1

.2. In a spark plug having an outer jacket, an insulator secured in thejacket and having an outer end socket and an axial electrode throughsaid insulator; a detachable cap. associated with 105 the outer end ofthe insulator and provided with a bore for the reception of anelectrical conductor, means in the cap for clamping said conductor inplace, said insulator and cap being provided, one with a sleeve and the"other with 110 prongs which fit in the sleeve to provide anelectricalconnection between said conductor and electrode. r

3. ,A' terminal connector for a spark plug, said I plug having a deepend socket withgan electrode flexible prongs in said socket, saidconnector comprising a detachable cap provided with aitubular extensionfitted closely into said socket said-extensicnbeing provided with anaxial bore, a metallic plug in said bore and a metallic sleeve (liningthe inner end of said bore and electrically

